1. Field of the Invention
The present invention relates to an ink jet recording apparatus having wiping means for cleaning the ink discharge port faces of the recording heads of the apparatus and to a method of cleaning such apparatus.
2. Related Background Art
An ink jet recording apparatus is such that ink is supplied into a recording head, discharge energy generating means (an electro-thermal converting member such as a heat generating resistor element or an electro-mechanical converting member such as a piezo element corresponding to an ink discharge port formed in the front face of the recording head) is driven on the basis of a data signal, ink is caused to fly from the ink discharge port toward a sheet (a recording medium such as paper or plastic thin film) and droplets of this ink are caused to adhere thereto, thereby accomplishing recording.
In an ink jet recording apparatus of this type, for the purpose of preventing the ink discharge port from being clogged due to the increased viscosity of ink resulting from the evaporation of the solvent in the ink, the desiccation of the ink, the adherence of dust or the entry of bubbles, there is provided restoring means for carrying out the capping of the ink discharge port or the cleaning of the ink discharge port face as by wiping.
The function of such restoring means can be divided broadly into the function of cleaning the ink discharge port face and the ink suction function of removing bubbles in the ink discharge port and ink which has increased in viscosity.
Now, in an ink jet recording apparatus for color images, use may be made of inks of plural colors and a plurality of recording heads corresponding to the respective colors. In such case, the colors of the inks used are usually four colors such as cyan, magenta, yellow and black.
Also, in some cases, recording is effected by the use of a plurality of inks identical in hue and differing in light and shade, and again in such cases, a plurality of recording heads are carried on the apparatus in conformity with the number of the inks.
In an ink jet recording apparatus provided with a plurality of recording heads for discharging such inks of plural colors respectively, cleaning means for cleaning the ink discharge port face of each recording head becomes necessary.
In such case, the provision of cleaning means for each recording head has led to the problem that the number of parts is increased and the structure of the apparatus becomes complex and the reliability of the apparatus is reduced. Also, juxtaposition of the cleaning means has led to a greater width of the recording apparatus, which in turn has prevented the apparatus from being made compact and light in weight.
If, therefore, all the ink discharge port faces of the plurality of recording heads are cleaned by a single cleaning means, there has sometimes arisen the problem that mixing of the inks of plural colors occurs on the cleaning means while the cleaning is repeatedly effected. This has sometimes resulted in the occurrence of the problem that the mixed inks having adhered to the cleaning means adhere from the cleaning means back to the ink discharge ports and the colors of the inks discharged from the ink discharge ports are changed thereby during the recording operation.